In recent years, display elements of image display devices including television receivers are shifting from conventional cathode-ray tube displays to thin display panels such as liquid crystal panels and plasma display panels. With the thin display panels, thin image display devices can be provided. A liquid crystal display device requires a backlight unit as a separate lighting device because a liquid crystal panel used therein is not a light-emitting component. The backlight unit is classified broadly into a direct type and an edge light type according to the mechanism of the backlight unit. To achieve a further reduction in thickness of the liquid crystal display device, it is preferable to use an edge light type backlight unit. Examples thereof disclosed in Patent Documents 1 and 2 mentioned below are known.
Patent Document 1: Japanese Unexamined Patent Publication No. 2001-92370
Patent Document 2: Japanese Unexamined Patent Publication No. 2001-93321